[Unstable/OEM-5.14] [PATCH 1/1] UBUNTU: SAUCE: PM: ACPI: reboot: Reinstate S5 for reboot

[Kai-Heng Feng]

BugLink: https://bugs.launchpad.net/bugs/1951055

The patch was in upstream as commit d60cd06331a3 "PM: ACPI: reboot: Use
S5 for reboot", but later got reverted by commit 9d3fcb28f9b9 because
reboot caused kernel panic on one system.

The most likely culprit is driver's reboot notifier callback and/or
shutdown callback didn't handle reboot properly. However, the affected
user didn't plan to find the root cause and just wanted a simple revert.

This patch is however quite important for many ACPI based system, as
many reboot stress woe can be addressed by it.

Signed-off-by: Kai-Heng Feng <kai.heng.feng at canonical.com>
---
 kernel/reboot.c | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/kernel/reboot.c b/kernel/reboot.c
index f7440c0c7e434..914fb6a288238 100644
--- a/kernel/reboot.c
+++ b/kernel/reboot.c
@@ -245,6 +245,8 @@ void migrate_to_reboot_cpu(void)
 void kernel_restart(char *cmd)
 {
 	kernel_restart_prepare(cmd);
+	if (pm_power_off_prepare)
+		pm_power_off_prepare();
 	migrate_to_reboot_cpu();
 	syscore_shutdown();
 	if (!cmd)
-- 
2.32.0